re atc tape. the time interval between 370 first on radio and signing off is 53 minutes. in the report the tape covering that time period only lasts 7 minutes so there must be plenty of splices perhaps explaining the noises-off. there were 7 minutes of real time between the repeats of level at 350. I am curious about another tape I have heard which had lumpur radar tell 370 to contact HCM three times. the aircraft did not respond until the third. will try to find tape again.